BackgroundAccording to some reports, left hemidiaphragmatic paralysis due to phrenic nerve injury may occur following cardiac surgery. The purpose of this study was to document the effects on phrenic nerve injury of whole body hypothermia, use of ice-slush around the heart and mammary artery harvesting.MethodsElectrophysiology of phrenic nerves was studied bilaterally in 78 subjects before and three weeks after cardiac or peripheral vascular surgery. In 49 patients, coronary artery bypass grafting (CABG) and heart valve replacement with moderate hypothermic (mean 28°C) cardiopulmonary bypass (CPB) were performed. In the other 29, CABG with beating heart was performed, or, in several cases, peripheral vascular surgery with normothermia.ResultsIn all patients, measurements of bilateral phrenic nerve function were within normal limits before surgery. Three weeks after surgery, left phrenic nerve function was absent in five patients in the CPB and hypothermia group (3 in CABG and 2 in valve replacement). No phrenic nerve dysfunction was observed after surgery in the CABG with beating heart (no CPB) or the peripheral vascular groups. Except in the five patients with left phrenic nerve paralysis, mean phrenic nerve conduction latency time (ms) and amplitude (mV) did not differ statistically before and after surgery in either group (p > 0.05).ConclusionsOur results indicate that CPB with hypothermia and local ice-slush application around the heart play a role in phrenic nerve injury following cardiac surgery. Furthermore, phrenic nerve injury during cardiac surgery occurred in 10.2 % of our patients (CABG with CPB plus valve surgery).

This study investigated the role of systemic inflammation in the development of atrial fibrillation (AF) after coronary artery bypass grafting (CABG). CABG was performed using cardiopulmonary bypass in 77 patients. Pre-operative AF was present in six patients (7.8%) and postoperative AF developed in 13 (18.3%) of the 71 patients with pre-operative sinus rhythm. Post-operative mediastinal drainage was significantly increased in patients with post-operative AF compared with those with sinus rhythm. Plasma E-selectin, P-selectin and vascular cell adhesion molecule levels were not significantly different between patients with pre- and post-operative sinus rhythm, those with pre-operative sinus rhythm and post-operative AF, and those with pre- and post-operative AF. There were significant differences between pre- and post-operative C-reactive protein, interleukin (IL)-6 and IL-10 levels within all three groups, but no differences in these parameters between the groups. Thus, in all groups there were significant alterations in mediators indicative of systemic inflammation following CABG, but comparisons between the groups revealed no differences predictive of AF.

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Administration of vitamin E into the coronary arteries before removal of the aortic cross-clamp can reduce myocardial cell injury and protect the myocardium from ischemia-reperfusion injury.

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